Whither goes winter weather?

October 29, 2010

Caught between the Great Basin to the east and Mojave Desert to the south, halfway between Southern and Northern California, backed by some of the highest mountains on the continent, Mammoth is a study in convergences and contrasts.

Its weather is no exception. High mountains do make their own weather to some extent, or block, mitigate or amplify whatâ€™s already out there.

Add the fact that Mammoth is almost precisely on the forecasting boundary between Northern and Southern California.

Then add the fact that the east and west sides of the Sierra can, and often do, react very differently to even the most accurately predicted weather systems and things get complicated pretty quickly.

â€śThis area is known as one of the most difficult in the country to predict the weather for,â€ť said Scott McGuire, a meteorologist in the Reno office of the National Weather Service. Part of that is due to the above factors. Another, lesser-known factor is a lack of data coming in from the Pacific, where most of the countryâ€™s storms originate, he said.

â€śBy the time a weather system gets inland, there is good data for it since it has already traveled through data collection points,â€ť he said.

â€śBut there is simply no place in the Pacific to set up instruments, until you get about 75 miles offshore.
â€śWe are like the first page in a book, the Midwest the middle, the East Coast the last page. By the time the book is read, you know the outcome. But not if you only have the first page.â€ť

Just try and tell that to Mammoth residents this time of year.

Already especially weather aware, locals turn into fanatics this time of year, poking, prying, talking, eying pinyon nuts and caterpillar bandwidths, watching the squirrels, checking to see if their dogâ€™s coat is growing in exceptionally thick (a good thing) or is sticking to short (a bad thing).
What this winter will be like hangs in the air like a mantra.

What will this winter be like?

Extreme and unpredictable.

Thatâ€™s how the three weather experts the MT talked to summed it up.

â€śI think no matter what happens, whether this is a wetter than normal winter or a drier one, it is going to be a very memorable winter, very cold, extreme variability, some cold storms, some wet ones, maybe even a Pineapple Express connection,â€ť said Mammothâ€™s own weather guru, Howard Sheckter.

In a year already noted by the National Oceanic and Atmospheric Administration as the fourth most extreme on record, Sheckterâ€™s prediction matches other local experts.

â€śIt does look like we are more likely than most years to see some extreme weather events,â€ť McGuire said.

There are a series of globe-wide weather related events all converging together this winter. In response, weather forecasters across the country are sounding the alarm, letting cities and citizens know this might be a winter to remember, whether it means a likely very wet winter in the Pacific Northwest, or a likely extreme drought in the Southwest.

One of these factors, at least, is something familiar to any Mammoth local whoâ€™s been around a while, where the words El NiĂ±o and La NiĂ±a winters are as common as baseball terms are to city-dwellers.

â€śWhat we are seeing is a rapid change from an El NiĂ±o winter to a La Nina winter, something that normally happens in three or four years,â€ť said longtime local avalanche forecaster Sue Burak, who was home for the weekend and is completing her masterâ€™s degree in hydrology at the University of Reno.

â€śThis year, it changed over in one year, and not only that, it shifted to what we now know is one of the strongest La NiĂ±aâ€™s on record.â€ť

What that means for Mammoth is still almost perfectly uncertain, she and McGuire both said.

Thatâ€™s because a La NiĂ±a winter can go either way for us here in Mammoth; either to above normal precipitation or to below normal.

In fact, the Central Sierra is smack dab in the very middle of the big, uncertain band for this yearâ€™s winter predictions released just this week by NOAA, where even the most sophisticated forecasts say its a 50/50 chance for either option.

On top of that, a study done of the four other times when an El NiĂ±o year has shifted to a La NiĂ±a pattern in one season shows another precise uncertainty: In two of those years, it was a wetter than normal winter and in two, it was a drier than normal winter, McGuire said.